/**
 *@ClassName NullDemo
 *
 *@Author ykx
 *@Date  2024/6/17 15:09
 *@Version 1.0
 */
fun main(args: Array<String>) {
    var result1 = heat("油")
    println(result1)

    var result2 = heat(null)

    println(result2)
}

fun heat(str: String?): String {
    return "热$str"
}